Samuel Yates began, and this site continues, a database of the largest known primes. Primes in that database are assigned a proof-code to show who should be credited with the discovery as well as what programs and projects they used. (Discoverers have one prover-entry, but may have many proof-codes because they use a variety of programs...) This page provides data on x28, one of those codes.

Proving primality using a test for numbers of the form
A23n+1, n odd,
described in a paper published by me and Pedro Berrizbeitia
in the Proceedings of the American Mathematical Society 130
(2002), 363-365.

I have several computers in the mathematics department
running a program written in C testing these numbers.